When is the best time to apply wheat herbicide?

Wheat herbicide is generally best sprayed when soil moisture reaches 40%-60%. When spraying, the amount must be controlled, and if there is a temperature drop within 3 days before application, do not spray, to avoid loss of efficacy. Available agents include mesosulfuron-methyl, flucarbazone-sodium, fenoxaprop-p-ethyl, clodinafop-propargyl, fluoroglycofen-ethyl, thifensulfuron-methyl, etc.

What are the wheat herbicides?

Generally, the weeds in wheat fields can be divided into two types: broadleaf weeds and grass weeds.

1. Wheat field herbicides for broadleaf weeds: tribenuron-methyl, bensulfuron-methyl, carfentrazone-ethyl, pyroxsulam, florasulam, MCPA, fluoroglycofen-ethyl, thifensulfuron-methyl, and 2,4-D butyl ester, etc.

2. Wheat field herbicides for broadleaf weeds: mesosulfuron-methyl, flucarbazone-sodium, fenoxaprop-p-ethyl, and clodinafop-propargyl, etc.

I. Fenoxaprop-p-ethyl

1. Fenoxaprop-p-ethyl is often used as a grass herbicide in wheat fields; for example, it gives good control of Japanese alopecurus (Alopecurus japonicus), rigid ryegrass (Sclerochloa kengiana), wild oat (Avena fatua), alopecurus (Alopecurus aequalis), Beckmannia syzigachne, and ryegrass (Lolium), etc., but its control of brome (Bromus) is poor.

2. The application period for fenoxaprop-p-ethyl is similar to that for jointed goatgrass (Aegilops tauschii); it is recommended to use it when the weeds are at the 2-4 leaf stage. The later the timing, the worse the control effect, especially after the weeds begin tillering, when control becomes even more difficult.

3. If it is sprayed when the temperature is relatively low, leaf yellowing may occur; mild cases can recover on their own, and in severe cases, spraying clean water, brassinosteroid, or foliar fertilizer can help relieve it.

II. Clodinafop-propargyl

1. Clodinafop-propargyl has a relatively wide range of applications; for example, it gives good control of rigid ryegrass (Sclerochloa kengiana), Beckmannia syzigachne, wild oat (Avena fatua), alopecurus (Alopecurus aequalis), Japanese alopecurus (Alopecurus japonicus), and Polypogon fugax, etc. Under complex external conditions, such as use at low temperatures, it can also produce a good effect, but clodinafop-propargyl kills weeds relatively slowly.

2. Generally, the effect can be seen about one week after application, and by about 20 days the weeds are almost completely dead. It is recommended to apply it when the weeds are at the 2-4 leaf stage; the later the timing, the worse the control effect.

3. In recent years, many farmers have reported that weeds have developed resistance to clodinafop-propargyl; for example, the control effect on Japanese alopecurus and wild oat has noticeably declined.

III. Mesosulfuron-methyl

1. Mesosulfuron-methyl is generally used more for controlling jointed goatgrass (Aegilops tauschii); this agent can not only control jointed goatgrass but also control grass weeds.

2. Its residue time is relatively short and it has no impact on crops.

3. The disadvantage of this agent is its relatively high cost, about 30 yuan per mu or possibly more; its application technique is demanding, and improper application can easily cause herbicide damage to wheat, such as in low-temperature weather or with excessive or uneven application, so reasonable application should be noted during use.

IV. Pyroxsulam

1. Pyroxsulam is also widely used; it can control not only grassy weeds but also a small portion of broadleaf weeds, such as brome (Bromus), wild oat, and rigid ryegrass (Sclerochloa kengiana), etc.

2. This agent is relatively less widespread, so resistance to it is not very great; if other herbicides develop resistance, this agent can be switched to, and it is relatively safe.

3. Its disadvantages are that if it encounters adverse weather factors such as weak wheat seedlings and low temperatures, it can easily cause herbicide damage, and its cost is relatively high.

The above is the relevant introduction on when is the best time to apply wheat herbicide, and we hope it is helpful to everyone.